title: Isocitrate dehydrogenase 1 mutant R132H sensitizes glioma cells to BCNU-induced oxidative stress and cell death.
abstract: Isocitrate dehydrogenase 1 (IDH1) decarboxylates isocitrate to α-ketoglutarate (α-KG) leading to generation of NADPH, which is required to regenerate reduced glutathione (GSH), the major cellular ROS scavenger. Mutation of R132 of IDH1 abrogates generation of α-KG and leads to conversion of α-KG to 2-hydroxyglutarate. We hypothesized that glioma cells expressing mutant IDH1 have a diminished antioxidative capacity and therefore may encounter an ensuing loss of cytoprotection under conditions of oxidative stress. Our study was performed with LN229 cells stably overexpressing IDH1 R132H and wild type IDH1 or with a lentiviral IDH1 knockdown. Quantification of GSH under basal conditions and following treatment with the glutathione reductase inhibitor BCNU revealed significantly lower GSH levels in IDH1 R132H expressing cells and IDH1 KD cells compared to their respective controls. FACS analysis of cell death and ROS production also demonstrated an increased sensitivity of IDH1-R132H-expressing cells and IDH1 KD cells to BCNU, but not to temozolomide. The sensitivity of IDH1-R132H-expressing cells and IDH1 KD cells to ROS induction and cell death was further enhanced with the transaminase inhibitor aminooxyacetic acid and under glutamine free conditions, indicating that these cells were more addicted to glutaminolysis. Increased sensitivity to BCNU-induced ROS production and cell death was confirmed in HEK293 cells inducibly expressing the IDH1 mutants R132H, R132C and R132L. Based on these findings we propose that in addition to its established pro-tumorigenic effects, mutant IDH1 may also limit the resistance of gliomas to specific death stimuli, therefore opening new perspectives for therapy.
authors.affiliation: Experimental Neurosurgery, Neuroscience Center, Goethe University Hospital, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.
authors.forename: Isabelle Vanessa
authors.initials: IV
authors.lastname: Mohrenz
authors.affiliation: Experimental Neurosurgery, Neuroscience Center, Goethe University Hospital, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Antonietti
authors.affiliation: Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Pusch
authors.affiliation: Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.|Department of Neuropathology, Institute of Pathology, Ruprecht-Karls-University Heidelberg, INF 224, 69120, Heidelberg, Germany.
authors.forename: David
authors.initials: D
authors.lastname: Capper
authors.affiliation: Department of Neuropathology, Institute of Pathology, Ruprecht-Karls-University Heidelberg, INF 224, 69120, Heidelberg, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Balss
authors.affiliation: Experimental Neurosurgery, Neuroscience Center, Goethe University Hospital, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.
authors.forename: Sophia
authors.initials: S
authors.lastname: Voigt
authors.affiliation: Department of Neuropathology, Institute of Pathology, Ruprecht-Karls-University Heidelberg, INF 224, 69120, Heidelberg, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Weissert
authors.affiliation: Experimental Neurosurgery, Neuroscience Center, Goethe University Hospital, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.
authors.forename: Alicia
authors.initials: A
authors.lastname: Mukrowsky
authors.affiliation: Institute of Biological Chemistry and Nutrition, University of Hohenheim, 70593, Stuttgart, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Frank
authors.affiliation: Department of Neurosurgery, Goethe University Hospital, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Senft
authors.affiliation: Department of Neurosurgery, Goethe University Hospital, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Seifert
authors.affiliation: Clinical Cooperation Unit Neuropathology, German Cancer Research Center (DKFZ), 69120, Heidelberg, Germany.|Department of Neuropathology, Institute of Pathology, Ruprecht-Karls-University Heidelberg, INF 224, 69120, Heidelberg, Germany.
authors.forename: Andreas
authors.initials: A
authors.lastname: von Deimling
authors.affiliation: Experimental Neurosurgery, Neuroscience Center, Goethe University Hospital, Theodor-Stern-Kai 7, 60590, Frankfurt, Germany. koegel@em.uni-frankfurt.de.
authors.forename: Donat
authors.initials: D
authors.lastname: Kögel
mesh_terms: D000625:Aminooxyacetic Acid / Q000494:pharmacology; D018906:Antineoplastic Agents, Alkylating / Q000494:pharmacology*; D002330:Carmustine / Q000494:pharmacology*; D016923:Cell Death / Q000187:drug effects; D045744:Cell Line, Tumor; D003606:Dacarbazine / Q000031:analogs & derivatives / Q000494:pharmacology; D019008:Drug Resistance, Neoplasm / Q000187:drug effects* / Q000235:genetics; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015972:Gene Expression Regulation, Neoplastic; D005973:Glutamine / Q000172:deficiency; D057809:HEK293 Cells; D006801:Humans; D007521:Isocitrate Dehydrogenase / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D009154:Mutation; D018384:Oxidative Stress; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D000077204:Temozolomide
chemical_list: D018906:Antineoplastic Agents, Alkylating; D004791:Enzyme Inhibitors; D034741:RNA, Small Interfering; D005973:Glutamine; D000625:Aminooxyacetic Acid; D003606:Dacarbazine; D007521:Isocitrate Dehydrogenase; C543588:IDH1 protein, human; D002330:Carmustine; D000077204:Temozolomide